Organoruthenium Complexes Containing Phosphinodicarboxamide Ligands

Ruthenium complexes of phosphinocarboxamide ligands, and their use to form metallacycles using halide abstraction/deprotonation reactions are reported. Thus, [Ru(p-cym){PPh2C(=O)NHR}Cl2; R = iPr (1), Ph (2), p-tol (3)] and [Ru(p-cym){PPh2C(=O)N(R)C(=O)N(H)R}Cl2; R = Ph (4), p-tol (5)] were synthesized from [(p-cym)RuCl2]2 (p-cym = para-cymene) and phosphinocarboxamides or phosphinodicarboxamides, respectively. Single-crystal X-ray diffraction measurements on 1-5 reveal coordination to ruthenium through the phosphorus donor, with an intramolecular hydrogen bond between the amine-bound proton and a metal-bound chloride. Six-membered metallacycles formed by halide abstraction/deprotonation of complexes 4 and 5 afforded [Ru(p-cym){& kappa;2-P,N-PPh2C(=O)N(R)C(=O)NR}Cl] [R = Ph (6), p-tol (7)]. These species exist as a mixture of two rotational isomers in solution, as demonstrated by NMR spectroscopy.

Automated summary

This study reports the synthesis of ruthenium complexes with phosphinocarboxamide ligands and their use in forming metallacycles through halide abstraction/deprotonation reactions. The coordination and structure of these complexes were studied using X-ray diffraction and NMR spectroscopy, revealing the presence of intramolecular hydrogen bonding and rotational isomers in solution.